1. Field of the Invention
The present invention relates to a tubular membrane module (hereinafter sometimes referred to as a module) for separation having an ultrafiltration membrane and a low pressure reverse osmosis membrane, and more particularly to a membrane module head which is formed of plastics so as to be light and has high productivity.
2. Desciption of the Prior Art
Typically, a tubular module is disclosed in U.S. Pat. No. 4,704,205 assigned to Daicel Chemical Industries, Ltd. In general, a module is widely used for concentration , separation or purification of a liquid. Since a membrane is provided on an inner surface of a support tube, the tubular membrane can be pressure-resistant, In addition, the module is tube-shaped so that a structure thereof can be simplified.
However, since a pressure is applied on a head in a direction of a central axis of the tubular membrane, a head is made thicker in consideration of pressure-resistance. Consequently, a variety of problems are caused. Therefore, it is desired that the head has the simplified structure. Conventionally, the entire head is made of metal or a metallic U bend is embedded in a plastic head. In the former case, since a U passage is provided in the head, the head is increased in cost and made too heavy. Consequently, it is difficult to provide or convey the module. In the latter case, although the head is made slightly lighter as compared with the former case, it is difficult to center a lot of U bends.